(1) Field of the Invention
The present invention relates to rollers for a lithograph and producing method of these rollers. More particularly, the present invention relates to rollers assembled in an ink supplying system of the lithograph, which uses ink and water, to perform ink distributing and excess ink removing works in addition to an ink supplying work. Further, the present invention relates to rollers which are auxiliarily used to ensure ink-supplying at a constant rate, and the rollers subjected to be contacted with a doctor blade.
(2) Description of the Prior Art
Such type rollers have been provided by following prior arts.
(A) Japanese Patent Application Laid-Open Publication No. 58-42463,
"Mesh Roller for an Offset Printing"
(B) Japanese Patent Application Laid-Open Publication No. 58-56855,
"Mesh Roller for an Offset Printing"
(C) Japanese Patent Application Laid-Open Publication No. 58-56856,
"Mesh Roller for an Offset Printing"
(D) Japanese Patent Application Laid-Open Publication No. 59-204558,
"Mesh Roller for a Lithograph"
(E) Japanese Patent Application Laid-Open Publication No. 61-68250,
"Ink Supplying Roller with Mesuring, and the Producting Method of the Roller and Ink Applying Apparatus"
(F) Japanese Patent Application Laid-Open Publication No. 61-181645,
"Ink Measuring Roller for a Lithograph"
(G) Japanese Patent Application Laid-Open Publication No. 61-181646,
"Ink Measuring Roller for a Lithograph"
(H) US. Patent Publication No. 4,301,730,
"ANILOX ROLL AND METHOD OF MAKING THE SAME"
(I) Japanese Patent Application Laid-Open Publication No. 60-44394,
"Ink Roller"
Further, the non-opened prior arts provided by the same applicant of the invention are as follows.
(J) Japanese Patent Application No. 60-187148,
"Mesh Roller for a Lithograph"
(K) Japanese Patent Application No. 61-119901,
"Mesh Roller and Method of Making the Same"
(L) Japanese Patent Application No. 61-126686,
"Mesh Roller for a Lithograph"
(M) Japanese Patent Application No. 61-68084,
"Roller"
The above listed prior arts will be briefly described.
The reference (A) entitled "Mesh Roller for an Offset Printing" relates to a mesh roller whose protruded sections are plated with a high anti-abrasive material and recessed sections are plated with an lipophilic material, wherein the lipophilic material is copper as a typical example, and the high anti-abrasive material is chromium as a typical example.
The reference (B) entitled "Mesh Roller for an Offset Printing" relates to (a) a mesh roller whose uneven surface is coated with a chromium layer, the surface layer of which is formed in a porous structure and soaked with oil to form a lipophilic layer, and (b) a mesh roller whose uneven surface is coated with a ceramic layer, pin holes formed in which are soaked with oil to form a lipophilic layer.
The reference (C) entitled "Mesh Roller for an Offset Printing" relates to (a) a mesh roller formed with a beryllium-copper layer by a plasma deposition whose surface layer is formed in a mesh shape uneveness and hardened by a heat treatment, and (b) a mesh roller formed with a beryllium-copper layer by a plasma deposition whose surface layer being formed in a mesh shape, and hardened by a heat treatment, and the protruded sections of the uneven surface are only plated with chromium.
The reference (D) entitled "Mesh Roller for a Lithograph" relates to (a) a mesh roller comprising a steel base whose surface is formed with a hardened layer and whose recessed sections are plated with a lipophilic material, (b) a mesh roller comprising a steel base whose surface is formed with a hardened layer by a nitriding treatment and whose recessed sections are plated with a lipophilic material, (c) a mesh roller comprising a steel base whose surface is formed with a hardened layer having a Vickers hardness of at least 1000 Hv by a nitriding treatment and whose recessed sections are plated with a lipophilic material, (d) a mesh roller comprising a steel base whose surface is formed with a handened layer and whose recessed sections are plated with copper as a lipophilic material, and (e) a mesh roller comprising a steel base whose surface is formed with a hardened layer and whose recessed sections are plated with copper by a process including a first step for plating over all surface and second step for removing the plated layer from the projected sections.
The reference (E) entitled "Ink Supplying Roller with Mesuring, and the Producing Method of the Roller and Ink Applying Apparatus" relates to an ink supplying roller with measuring whose steel base is formed with a nitrized inner layer having a Rockwell hardness of at least 55 Rc whose thickness is 3 mils or more, and a fine porous oxized outer layer composed of Fe.sub.3 o.sub.4.
The reference (F) entitled "Ink Measuring Roller for a Lithograph" relates to an ink measuring roller whose surface is plated with a electroless nickle layer having a Rockwell hardness of at least 50 Rc and a copper layer on the nickle layer.
The reference (G) entitled "Ink Measuring Roller for a Lithograph" relates to (a) an ink roller whose surface is wholly covered with a lipophilic material layer and further formed with a porous ceramic layer, (b) an ink roller whose surface is wholly covered with copper layer as a lipophilic material and further formed with a porous ceramic layer, (c) an ink roller whose surface is wholly covered with a lipophilic material layer and further formed with a porous ceramic layer composed of aluminum oxide (Al.sub.2 O.sub.3), and (d) an ink roller whose serface is wholly covered with copper layer as a lipophilic material and futher formed with a porous ceramic layer composed of aluminum oxide (Al.sub.2 O.sub.3).
Following references teach rollers coated with ceramics.
The reference (H) entitled "ANILOX ROLL AND METHOD OF MAKING THE SAME" relates to a mesh roller whose surface is coated with a ceramic layer by a melt injection coating and further coated with a polymer sealing material to seal the pores in the ceramic layer.
The reference (I) entitled "Ink Roller" relates to a roller whose steel surface is coated with a porous ceramic layer by a melt injection coating and further coated with a lipophilic resin to seal the pores in the ceramic layer.
Following references provided by the same applicant of this invention teach mesh rollers for an offset printing.
The reference (J) entitled "Mesh Roller for Offset Printing" relates to (a) a mesh roller whose steel surface is wholly coated with a ceramic layer and further plated with a lipophilic material, and (b) a mesh roller whose steel surface is wholly coated with a ceramic layer and further plated with a lipophilic material to form the even surface where the ceramic material and the lipophilic material are finely mixed.
The reference (K) entitled "Mesh Roller and Method of Making the Same" relates to (a) a mesh roller whose each projected section includes a center section composed of a mother material of the roller which has ink philic and hydrophobic properties, and an edge section of the projected section composed of a surface layer of recessed section which is harder than the mother material, (b) a mesh roller defined by (a) whose recessed surface layer is further coated with a material having ink philic and hydrophobic properties, (c) a mesh roller defined by (a) and (b) whose mother material is composed of copper or copper alloy, and recessed surface layer is composed of ceramic, and (d) a mesh roller defined by (a), (b) and (c) whose mother material is provided with a pre-plating layer.
The reference L) entitled "Mesh Roller for Lithograph" relates to (a) a mesh roller whose steel surface is wholly coated with an ultra-hard material and further coated or plated with a lipophilic material, (b) a mesh roller whose steel surface is wholly coated with an ultra-hard material and further coated or plated with a lipophilic material to form the whole surface except for the recessed sections where the ultra-hard material and the lipophilic material are finely mixed, (c) a mesh roller whose steel surface is wholly coated with the mixture of ultra-hard material and lipophilic material to form a surface layer with finely mixed of them, (d) mesh rollers defined by (a), (b), and (c) wherein the ultra-hard material is selected from ceramics, (e) mesh rollers defined by (a), (b), and (c) wherein the ultra-hard material is tungsten carbide, (f) mesh rollers defined by (a), (b), and (c) wherein the lipophilic material is copper, and (g) mesh rollers defined by (a), (b), and (c) wherein the lipophilic material is copper alloy.
Following reference provided by the same applicant of the invention teaches a roller for a rotary press.
The reference (M) entitled "Roller" relates to (a) a roller whose surface is provided with continuous or non-continuous belts made of high anti-abrasive material which are arranged to meet at non-right angle with the axis of the roller, (b) a roller defined by (a) wherein the belts are made of the same material as the roller mother material, (c) a roller defined by (a) wherein the belts are made of a high hard material, (d) a roller defined by (a) wherein the belts are made of ceramics, (e) a roller defined by (a) wherein the belts are made of tungsten carbide, (f) a roller defined by (a) wherein the surface except for the belts are made of the same material as the roller mother material, (g) a roller defined by (a) wherein the surface except for the belts is made of a lipophilic material, (h) a roller defined by (a) wherein the surface except for the belts is made of copper or cpper alloy as a lipophilic material, (i) a roller defined by (a) wherein the surface except for the belts are made of a hydrophilic material, (j) a roller defined by (a) wherein the surface except for the belts is made of chromium as a hydrophilic material, (k) mesh roller defined by (a), (b), (c), (d), (e), (f), (g), (h), (i) and (j) whose surfaces are formed with a regular arrangement of fine cells for measuring, and (1) mesh rollers defined by (a), (b), (c), (d), (e), (f), (g), (h), (i) and (j) whose surfaces are smooth.
The rollers for a lithgraph are required that the surface has lipophilic and hydrophobic property and a high abrasive property. These properties are not satisfied by the above mentioned references.
The references A, B, (b) of C, D, E, F, G and H disclose ink supplying rollers whose external surface is made of anti-abrasive materials such as chromium, nickle, ceramic in order to improve abrasive resistance against the abrasive motion of doctor blade. Although this constitution satisfies the purpose of improving the abrasive resistance, chromium, nickle, and ceramic may easily cause troubles during ink-supplying work because they are lipophilic but hydrophilic rather than hydrophobic. The ink on the roller surface may be replaced by water when water is mixed or remained in the ink supplying system.
The roller (a) of the reference C is provided with a copper alloy; i.e., beryllium-copper, to form a lipophilic and hydrophobic surface. Although the beryllium-copper is the hardest of copper alloys, its abrasive resistance against the doctor blade is not satisfied.
The reference I teaches a roller whose abrasive resistance is improved by use of ceramic and whose surface is provided with lipophilic and hydrophobic properties by use of a lipophilic resin. However, this roller surface is poor in workability so that fine cells can not be formed in the surface. Further, the roller surface is made of two materials; ceramic and lipophilic resin, having different thermal conductivity and thermal expansion rate. These two layers may be separated and the resin layer may be broken when the roller is alternatively subjected to the repetition of heating and cooling. Thus this roller can not be used for a long period.